Liquid filter and filter element

ABSTRACT

A liquid filter has a filter housing with a housing cup. A filter element of the liquid filter has a filter medium annularly surrounding a longitudinal axis of the filter element. The filter element has an extension part with lock groove. A lock device arranged at the housing cup has a lock element movable radially to the longitudinal axis. The lock element engages the lock groove in a locked state of the lock device and is disengaged in a release state. A filter element for the liquid filter has a filter medium annularly surrounding a longitudinal axis and an extension part with lock groove with rounded cross section. The lock groove is engaged by a lock element, movable radially relative to the longitudinal axis, of a lock device of a housing cup of the liquid filter in a locked state of the lock device and disengaged in a release state.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit under 35 U.S.C. 119(a) of GermanApplication No. 102022117115.9 filed on Jul. 8, 2022, in the GermanPatent Office, the entire disclosure of which is incorporated herein byreference for all purposes.

BACKGROUND

The invention concerns a liquid filter comprising a filter housing witha filter head and a housing cup and further comprising a filter elementwith a filter medium which surrounds a longitudinal axis annularly.

Such liquid filters are well known in the prior art. Such filters areused for filtering fuel or oil, for example.

For an exchange of the filter element, the housing cup is detached fromthe filter head. In order to avoid soiling and contamination of theenvironment, it is expedient in this context to remove the liquid fromthe housing cup prior to opening the filter housing or prior to removingthe filter element from the housing cup.

A liquid filter of the aforementioned kind is disclosed, for example, inDE 20 2008 013 578 U1. In this liquid filter, a drainage socket with adrainage channel is provided. The drainage socket can be moved between aclosed position and an open position. The drainage socket glides in thiscontext in a bore in the housing cup. The drainage socket interacts withthe filter element. For a detachable engagement, the drainage socket canbe screwed with an outer thread into an inner thread of an end plate ofthe filter element.

A similar liquid filter is disclosed in US 2017/0095759 A1. A drainvalve of this liquid filter comprises a valve body with an axial passageand a valve shaft which is embodied at a bottom cap of the filterelement. The valve body is movably guided in a bore of the housing cup.The valve shaft is provided with an outer thread for engagement in aninner thread of the valve body. In a groove of the valve shaft, anO-ring for sealing the valve shaft in relation to the valve body isarranged.

In the two aforementioned liquid filters, the respective threadconnection between the filter element and the drainage socket or valvebody must be released for exchanging the filter element. This entails acertain expenditure.

It is an object of the invention to design the exchange of a filterelement to be reliable, simple, and realizable particularly quickly.

SUMMARY

This object is solved by a liquid filter comprising a filter housingwith a filter head and a housing cup, a filter element with a filtermedium which surrounds a longitudinal axis annularly, wherein the filterelement comprises an extension part with a lock groove, wherein a lockdevice with at least one lock means movable radially in relation to thelongitudinal axis is provided at the housing cup, wherein the lock meansengages the lock groove in a locked state of the lock device and can bedisengaged from the lock groove in a release state of the lock device.

The object is further solved by a use of a filter element with a filtermedium, which surrounds a longitudinal axis annularly, in a liquidfilter embodied in accordance with the invention, wherein the filterelement comprises an extension part.

The object is further solved by a filter element, for a liquid filterembodied in accordance with the invention, the filter element comprisinga filter medium, which surrounds a longitudinal axis annularly, and anextension part with a lock groove, wherein the lock groove comprises arounded, in particular circular segment-shaped, cross section.

Preferred embodiments are disclosed in the respective dependent claimsand the description.

According to the invention, a liquid filter is provided. The liquidfilter comprises a filter housing with a filter head and a housing cup.The housing cup is in principle detachably connectable to the filterhead, for example, can be screwed onto the filter head. The liquidfilter comprises furthermore a filter element with a filter medium. Thefilter medium surrounds a longitudinal axis annularly. The filter mediumcan be comprised of folded paper. The filter element can be flowedthrough radially from the exterior to the interior. An interior which isenclosed by the filter medium forms in this case a clean side. Theliquid filter can be used for filtering fuel or oil. The liquid filtercan be used in a commercial vehicle, for example, a tractor orexcavator. The liquid filter, for example, can also be used forfiltering transmission oil of an electric motor of an electricallydriven motor vehicle.

According to the invention, the filter element comprises an extensionpart with a lock groove. The extension part extends generally parallelto the longitudinal axis, typically the extension part is arrangedconcentrically to the longitudinal axis. The extension part in generalprojects past an end face of the filter medium or an end disk at the endface. The extension part is typically coupled to the filter medium so asto be immobile.

Further according to the invention, a lock device with at least one lockmeans movable radially in relation to the longitudinal axis is providedat the housing cup. The lock device is typically arranged at a cupbottom of the housing cup. In a locked state of the lock device, the atleast one lock means engages the lock groove; in a release state of thelock device, the at least one lock means can be disengaged from the lockgroove. A movement of the at least one lock means comprises in thiscontext a movement component radial in relation to the longitudinalaxis. It is possible to provide more than one lock means, e.g., at leastthree, in particular precisely three, lock means can be provided.

In the locked state, the filter element is held safely at the housingcup by the engagement of the at least one lock means in the lock groove.In this way, it can be ensured that, when removing the housing cup fromthe filter head, the filter element remains in the housing cup and alsodoes not accidentally drop down during further handling. In order toremove the filter element from the housing cup, the locking action canbe quickly and easily released. A new filter element can then beinserted into the housing cup and locked at the latter. A displacementof the filter element in the housing cup during mounting at the filterhead can therefore be avoided.

Preferably, the lock groove comprises a rounded, in particular circularsegment-shaped, cross section. Such a shape of the lock groove can bemanufactured simply and enables a safe engagement of the lock means. Dueto the rounded shape, an advantageous force flow with minimal stresspeaks in the extension part is obtained.

The extension part and a support tube and/or an end disk of the filterelement together can be one piece. This simplifies the manufacture andensures a stable connection of the extension part at the filter medium.

The at least one lock means can be a ball. Balls can be obtainedinexpensively. In addition, when using balls as lock means, it can beavoided that they get jammed when establishing or releasing the lockingaction.

Particularly preferred, the at least one lock means is guided in aholder which is movable in particular along the longitudinal axisbetween a locked position and a release position. The holder enables, onthe one hand, guiding of the at least one lock means. On the other hand,the holder can simplify the release of the at least one lock means fromthe engagement in the lock groove, in particular when a plurality oflock means are provided. For the locked state of the lock device, theholder is moved into the locked position; for the release state of thelock device, the holder is moved into the release position.

Preferably, the holder is pretensioned into the locked position. Inparticular, the holder can be pretensioned away from a cup bottom of thehousing cup or toward the filter element. By means of the pretension, itcan be achieved that a locking action takes place upon insertion of afilter element without further ado. A spring element can be supportedwith one end at the holder, with the other end at the housing cup, inparticular at its cup bottom.

The holder can be received in a receptacle. The receptacle can form astop for the holder in the locked position. Preferably, the receptacleis locked at the housing cup. This simplifies mounting of the lockdevice.

Particularly preferred, the at least one lock means is supported at thereceptacle in the locked state of the lock device. The receptacle canthus ensure that the lock means is pushed radially inwardly in order toengage the lock groove. In particular, the receptacle can be conical.When the holder with the at least one lock means is transferred alongthe longitudinal axis into the locked position, the at least one lockmeans is pushed more and more radially inwardly. Conversely, the lockmeans can be pushed radially outwardly by insertion of the extensionpart into the lock device with axial movement of the holder. Theinsertion of a new filter element into the housing cup is thereforeparticularly comfortably designed because an additional actuation of thelock device is not required. Rather, it is sufficient to push the filterelement into the housing cup.

The lock device can comprise a grip piece for movement of the holder,wherein the grip piece is movable to a limited extent relative to theholder, in particular along the longitudinal axis. The release of thelocking action is simplified in this way. When using the liquid filter,the grip piece can be moved into a space-saving position of use. For anexchange of the filter element, the grip piece can be moved into ahandling position in which it can be easily gripped. The operation ofthe lock device is simplified in this way. The handling position istypically defined by a stop between the holder and the grip piece.

Preferably, the grip piece is pretensioned toward an outer side of thehousing cup. In this way, it can be achieved that the grip pieceautomatically is transferred into the handling position. The operationof the lock device is therefore particularly comfortably designed.

The lock device can be arranged at a drainage opening in the housingcup. Preferably, the filter housing comprises a closure screw for thedrainage opening. For operating the liquid filter, the drainage openingis closed by the closure screw. Prior to an exchange of the filterelement, the drainage opening is opened by removal of the closure screwso that the liquid can drain from the filter cup.

Particularly preferred, the grip piece for the holder is supported atthe closure screw when the closure screw closes—in a mounted state—thedrainage opening. When screwing in the closure screw, the grip piece isthus moved into the position of use. When removing the closure screw,the grip piece can pass automatically into the handling position, inparticular when it is appropriately pretensioned or due to the force ofgravity.

The extension part can comprise a continuous longitudinal opening. Thecontinuous longitudinal opening connects an interior of the filterelement in fluid communication with an axial end of the extension part.Liquid from the interior can thus be drained through the longitudinalopening. In the mounted state, the closure screw closes the drainageopening as well as the longitudinal opening. A flow of the liquid to befiltered bypassing the filter element can thus be prevented. Uponremoval of the closure screw, emptying of the region outside of thefilter element as well as of the interior of the filter element is madepossible instead.

Alternatively, the extension part can be of a closed design. Inparticular, the interior of the filter element can be fluid-tightlyclosed at the extension part.

The extension part can comprise a nose and a compensation elementmovable in relation to the nose. The compensation element is typicallymovable along the longitudinal axis in relation to the nose. In themounted state, the closure screw is coupled with the compensationelement, in particular by a seal element. The compensation element cancompensate movements between the filter cup, in particular the cupbottom, and the filter element. Such movements can occur, for example,in case of pulsations of the liquid pressure in the liquid filter. Incase of a pressure increase, the closure screw at the cup bottom movesaway from the filter head due to the elasticity of the housing cup. Thefilter element, on the one hand, is held in a seal seat at the filterhead; on the other hand, the filter element is typically connectedseal-tightly to the closure screw in operation. Movements at the sealinglocations can be avoided in that a movement possibility between the noseand the compensation element of the extension part is established. Thelock groove is typically embodied at the nose of the extension part;alternatively, the lock groove can be embodied at the compensationelement. The nose is in principle connected rigidly to the filtermedium, for example, by a support tube or an end disk. The nose and thesupport tube and/or the end disk can be embodied together as one piece.

The scope of the present invention includes also a use of a filterelement with a filter medium, which surrounds a longitudinal axisannularly, in a liquid filter according to the invention as describedabove, wherein the filter element comprises an extension part with alock groove. The filter element can comprise further features describedabove. The corresponding advantages can be utilized for the use of thefilter element in accordance with the invention.

The scope of the present invention also includes a filter element for anabove-described liquid filter according to the invention. The filterelement comprises a filter medium which surrounds a longitudinal axisannularly and an extension part with a lock groove. The lock groovecomprises a rounded, in particular circular segment-shaped, crosssection. Preferably, the extension part and a support tube and/or an enddisk of the filter element are embodied together as one piece. Thefilter element can comprise further features described above. When usingthe filter element according to the invention in a filter device, thecorresponding advantages can be utilized.

BRIEF DESCRIPTION OF DRAWINGS

Further features and advantages of the invention result from thefollowing detailed description of embodiments of the invention, from theclaims as well as with the aid of the Figures of the drawingillustrating details according to the invention. The aforementioned andstill further explained features can be realized individually bythemselves or several thereof in arbitrary expedient combinations invariants of the invention. The features illustrated in the drawing areillustrated such that the particularities according to the invention canbe made clearly visible.

FIG. 1 shows a liquid filter according to the invention with a filterelement according to the invention received in a filter housing in aschematic section view, wherein the filter element is locked at a lockdevice at a housing cup of the filter housing.

FIG. 2 shows a schematic enlarged illustration of a first embodiment ofthe liquid filter according to the invention in the region of the lockdevice in a locked state with screwed-in closure screw.

FIG. 3 shows the liquid filter of FIG. 2 with removed closure screw,wherein a grip piece of the lock device projects from the filter cup, ina schematic section view.

FIG. 4 shows the liquid filter of FIG. 2 in a release state with thefilter element released from the lock device, in a schematic sectionview.

FIG. 5 shows a schematic enlarged illustration of a second embodiment ofthe liquid filter according to the invention in the region of the lockdevice in a locked state with screwed-in closure screw.

FIG. 6 shows a schematic enlarged illustration of a third embodiment ofthe liquid filter according to the invention in the region of the lockdevice in a locked state with screwed-in closure screw.

DETAILED DESCRIPTION

FIG. 1 shows a liquid filter 10. The liquid filter 10 comprises a filterhousing 12 with a filter head 14 and a housing cup 16 screwed onto thefilter head 14. An inlet 18 for liquid to be filtered and an outlet 20for filtered liquid are formed at the filter head 14.

A filter element 22 of the liquid filter 10 is received in the filterhousing 12. The filter element 22 comprises a filter medium 24 whichsurrounds a longitudinal axis 26 annularly and encloses an interior 28.The filter medium 24 can be paper folded in a star shape. Here, thefilter medium 24 can be flowed through radially from the exterior to theinterior. The filter medium 24 is framed between an end disk 30 which iscorrelated with the filter head 14 and a cup-side end disk 32. Radiallyinwardly, the filter medium 24 is supported on a support tube 34.

A drainage opening 38 is formed in a cup bottom 36 of the housing cup16. The drainage opening 38 can be closed by insertion of a closurescrew 40 (as illustrated) or can be opened by removal of the closurescrew 40.

The housing cup 16 comprises a lock device 42 for locking the filterelement 22 at the housing cup 16. The lock device 42 is provided at thecup bottom 36 in the region of the drainage opening 38. The details ofthe lock device 42 and its interaction with the filter element 22 willbe explained in the following with the aid of different exemplaryembodiments.

FIG. 2 shows a detail of a first embodiment of the liquid filter 10 inthe region of the lock device 42. In FIG. 2 , the lock device 42 is in alocked state in which the filter element 22 is locked at the housing cup16.

The filter element 22 comprises an extension part 44. The extension part44 projects concentrically to the longitudinal axis 26 away from thefilter element 22, in particular, the extension part 44 projects pastthe cup-side end disk 32 in axial direction (in relation to thelongitudinal axis 26). The extension part 44 is here integrally formedas one piece together with the support tube 34.

A lock groove 46 is formed in the extension part 44. Presently, the lockgroove 46 comprises a rounded cross section. Concretely, the lock groove46 is formed by a circular segment-shaped recess in the extension part44.

In the locked state, at least one lock means 48 engages the lock groove46. The lock means 48 are here embodied as balls. Radially outwardly,the lock means 48 in the locked state engage a conical receptacle 50 ofthe lock device 42. The receptacle 50 is fastened at the housing cup 16,for example, locked thereat. The filter element 22, due to the lockmeans 48 supported between the lock groove 46 and the receptacle 50,cannot be removed from the housing cup 16 as long as the lock device 42is in the locked state.

The lock means 48 are guided in a holder 52. The holder 52 is movablewithin the receptacle 50 along the longitudinal axis 26. The holder 52is pretensioned by a spring element 54 into a locked position, here fromthe cup bottom 36 toward the filter element 22. In the locked position,the holder 52 is resting at the receptacle 50 which, in other words,forms a stop for the holder 52.

The extension part 44 comprises here a continuous longitudinal opening56. The longitudinal opening 56 opens the interior 28 in axial directionoutwardly.

FIG. 2 shows the closure screw 40 screwed into the drainage opening 38.The closure screw 40 closes thus the drainage opening 38. Furthermore,the closure screw 40 closes the longitudinal opening 56 of the extensionpart 44. For this purpose, a seal element 58 can be arranged between theextension part 44 and the closure screw 40.

In the embodiment illustrated in FIG. 2 , the lock device 42 comprises agrip piece 60 for the holder 52. The grip piece 60 is guided at theholder 52 so as to be slidable in longitudinal direction. Presently, thegrip piece 60 is pretensioned by a further spring element 62 away fromthe holder 52 toward an exterior side of the housing cup 16. When theclosure screw 40 is inserted, the grip piece 60 is thus pushed againstthe closure screw 40. The mounted closure screw 40 holds the grip piece60 in the illustrated position of use for a filtering operation of theliquid filter 10.

The grip piece 60 serves for releasing the locking action of the filterelement 22 at the housing cup 16. For an exchange of the filter element22, first the closure screw 40 is removed, see FIG. 3 . The liquidcontained in the housing cup 16 can thus drain through the drainageopening 38. In particular, liquid from the interior 28 of the filterelement 22 can be discharged through the longitudinal opening 56 in theextension part 44 and the drainage opening 38.

With the closure screw 40 removed, the spring element 62 pushes the grippiece 60 away from the holder 52 so that the grip piece 60 is moved intoa handling position in which it projects in axial direction away fromthe housing cup 16. In particular, grip depressions 61 at the grip piece60 can project past a bottom end of the housing cup 16. In the handlingposition, the grip piece 60 rests against the holder 52. In other words,a stop is established between the grip piece 60 and the holder 52 andlimits the movability of these two components relative to each other.

By pulling on the grip piece 60, the holder 52 can be moved into arelease position illustrated in FIG. 4 . By moving the holder 52 intothe release position, the lock device 42 is transferred into a releasestate. Since the holder 52 is moved away from the receptacle 50, thelock means 48 can move radially outwardly in radial guide recesses 63 inthe holder 52. Thus, the engagement of the lock means 48 in the lockgroove 46 can be released. The extension part 44 can be pulled out ofthe lock device 42; thus, the filter element 22 can also be removed fromthe housing cup 16.

Upon insertion of a (new) filter element 22, the free end of theextension part 44 pushes the holder 52 via the lock means 48 against theaction of the spring element 54 into the release position. In thiscontext, the closure screw 40 can already be mounted again. When thefilter element 22 is completely inserted, the lock means 48 move intothe lock groove 46 due to the spring pretension. The filter element 22is thus locked at the housing cup 16.

FIG. 5 shows a detail of a second embodiment of the liquid filter 10,which corresponds mostly to the first embodiment (compare FIGS. 2through 4 ), in the region of the lock device 42. In particular, thelock device 42 of the housing cup 16 of the second embodimentillustrated in FIG. 5 corresponds in its functional construction to thelock device 42 of the first embodiment illustrated in FIGS. 2 through 4and described above.

In the second embodiment illustrated in FIG. 5 , the filter element 22comprises a multi-part extension part 44. A nose 64 of the extensionpart 44 is rigidly connected to the filter medium 24. Here, the nose 64is formed as one piece together with the support tube 34. The lockgroove 46 is formed in the nose 64.

The extension part 44 comprises here furthermore a compensation element66 which is guided movably in longitudinal direction at the nose 64 andis held at the nose 64. The longitudinal opening 56 extends through thenose 64 as well as through the compensation element 66.

In the mounted state, the closure screw 40 closes the drainage opening38 as well as the longitudinal opening 56. For this purpose, the closurescrew 40 engages the compensation element 66. Presently, the closurescrew 40 is coupled by the seal element 58 to the compensation element66 in that the seal element 58 is compressed between the closure screw40 and the compensation element 66.

The movability of the compensation element 66 in relation to the nose 64enables movements of the closure screw 40 in relation to the filterelement 22 without this causing relative movements between the closurescrew 40 and the extension part 44 at the seal element 58.

FIG. 6 shows a detail of a third embodiment of the liquid filter 10,which corresponds mostly to the second embodiment (compare FIG. 5 ), inthe region of the lock device 42. In particular, the filter element 22of the third embodiment illustrated in FIG. 6 corresponds in itsfunctional configuration to the filter element 22 of the secondembodiment illustrated in FIG. 5 and described above.

In the third embodiment illustrated in FIG. 6 , there is no separategrip piece for the holder 52 provided. Here, grip depressions 61 aredirectly formed at the holder 52. After removal of the closure screw 40,the holder 52 remains initially in the illustrated locked position dueto the pretension of the spring element 54. For moving the holder 52into the release position, not illustrated in detail here, one mustreach into the drainage opening 38.

In summarizing, the invention concerns a liquid filter in which a filterelement can be locked at a housing cup. The filter element comprises anextension part with a lock groove. The lock groove can be formed as arounded, in particular circular segment-shaped, depression at theextension part. At the housing cup, a lock device is provided. Theextension part can be inserted into the lock device for locking. A lockmeans can be moved into the lock groove or can be disengaged from thelock groove. For this purpose, the lock means can be moved in particularin radial direction. The radial movability of the lock means can beestablished by a conical contact surface and an axially movable holderwhich entrains the lock means in axial direction but allows for radialmovements of the lock means.

1. A liquid filter comprising: a filter housing comprising a filter head and a housing cup; a filter element comprising a filter medium annularly surrounding a longitudinal axis of the filter element, wherein the filter element comprises an extension part provided with a lock groove; and a lock device comprising at least one lock means movable radially in relation to the longitudinal axis and arranged at the housing cup, wherein the at least one lock means engages the lock groove in a locked state of the lock device and is disengaged from the lock groove in a release state of the lock device.
 2. The liquid filter according to claim 1, wherein the lock groove comprises a rounded cross section.
 3. The liquid filter according to claim 2, wherein the rounded cross section is circular segment-shaped.
 4. The liquid filter according to claim 1, wherein the filter element further comprises a support tube and/or an end disk, and wherein the extension part and the support tube and/or the end disk are formed together as one piece.
 5. The liquid filter according to claim 1, wherein the at least one lock means is a ball.
 6. The liquid filter according to claim 1, further comprising a holder movable between a locked position and a release position, wherein the at least one lock means is guided in the holder.
 7. The liquid filter according to claim 6, wherein the holder is pretensioned into the locked position.
 8. The liquid filter according to claim 6, further comprising a receptacle, wherein the holder is received in the receptacle.
 9. The liquid filter according to claim 8, wherein the receptacle is locked at the housing cup.
 10. The liquid filter according to claim 8, wherein the at least one lock means is supported at the receptacle in the locked state.
 11. The liquid filter according to claim 6, wherein the lock device comprises a grip piece configured to move the holder, wherein the grip piece is movable to a limited extent in relation to the holder.
 12. The liquid filter according to claim 11, wherein the grip piece is pretensioned toward an outer side of the housing cup.
 13. The liquid filter according to claim 11, wherein the housing cup comprises a drainage opening, wherein the lock device is arranged at the drainage opening of the housing cup, and wherein the filter housing further comprises a closure screw configured to close the drainage opening of the housing cup in a mounted state of the closure screw.
 14. The liquid filter according to claim 13, wherein the grip piece is supported at the closure screw when the closure screw closes the drainage opening in the mounted state.
 15. The liquid filter according to claim 13, wherein the extension part comprises a continuous longitudinal opening, and wherein the closure screw closes the drainage opening of the housing cup and the continuous longitudinal opening in the mounted state.
 16. The liquid filter according to claim 13, wherein the extension part comprises a nose and a compensation element movable in relation to the nose, and wherein the closure screw is coupled to the compensation element in the mounted state.
 17. The liquid filter according to claim 16, wherein the closure screw is coupled to the compensation element by a seal element.
 18. A filter element for a liquid filter, the filter element comprising: a filter medium annularly surrounding a longitudinal axis of the filter element; and an extension part provided with a lock groove, wherein the lock groove comprises a rounded cross section, and wherein the lock groove is configured to: be engaged by at least one lock means movable radially in relation to the longitudinal axis, the at least one lock means being of a lock device of a housing cup of a filter housing of the liquid filter in a locked state of the lock device; and be disengaged by the at least one lock means in a release state of the lock device.
 19. The filter element according to claim 18, wherein the rounded cross section is circular segment-shaped.
 20. The filter element according to claim 18, further comprising a support tube and/or an end disk, wherein the extension part and the support tube and/or the end disk are formed together as one piece. 